Revolvers are customarily made to include a main frame or body portion, a handle or gripping portion at one end of the body portion, and a barrel with a rotatable cartridge cylinder mounted on the body. The body portion includes a trigger guard and trigger with a hammer which is pivotally mounted on the body above the handle portion and rearwardly of the cylinder. The hammer can be pivoted independently or in response to pulling the trigger so as to be forced rearwardly against the urging of a main spring until it moves past the center at which point it is driven forwardly to discharge or fire the weapon.
Safeties have been devised in the past for the purpose of preventing accidental discharge of firearms. Typically, safeties that have been designed for use with revolvers have required addition of parts or redesign of the weapon itself. Representative of said safeties are those disclosed in U.S. Pat. Nos. 573,736 to Wesson et al, 635,705 to Wesson et al, 3,422,559 to Wolloch, 792,381 to Allen, 3,978,603 and 4,091,557 to Murabito. The early patents to Allen and Wolloch may be generally characterized as providing some form of a spring-loaded plunger having a safety which will normally interfere with hammer movement until the plunger is selectively released by the thumb. In Wesson et al '736, the safety is activated only when the plunger is advanced manually to release the cylinder for reloading or cleaning. In the '603 patent to Murabito a thumbpiece engages a specially formed shoulder in a slotted portion or recess so as to override the stronger force of a compression spring. Similarly, in the more recent '557 patent to Murabito, a special safety device is added to a Ruger doubleaction revolver.
The Smith & Wesson revolvers, such as, the Model 10 Combat Magnum manufactured and sold by Smith & Wesson of Springfield, Mass., employ a thumbpiece on one side of the handle which serves as a release for the cylinder in order to permit loading of the cylinder with cartridges or bullets. In this relation, a bolt on the Smith & Wesson includes a nose which engages a center pin on the cylinder, and a thumbpiece must be positively advanced against the urging of a spring on the center pin in order to cause retraction of the center pin and release of the cylinder for loading. At the same time, the bolt is normally biased or urged in a direction so as to be clear of the path of the hammer. To my knowledge, however, no one has successfully devised a safety for the Smith & Wesson revolver in which the spring members acting in opposition to one another at opposite ends of the bolt are so designed that the relative spring force is balanced in such a way as to normally position an abutment on the bolt in the path of movement of the hammer so that the weapon can be fired only by a positive manual release or movement of the abutment out of the path of the hammer. It is therefore proposed in accordance with the present invention to devise a method and means for retrofitting weapons of this type such that they will be equipped with safeties but without requiring redesign or fabrication of the weapon itself, or the addition of special parts; yet to be able to incorporate into existing weapons a safety which both can be effectively disguised and will normally remain in a safety position until positively released.